The present invention relates to an electronic organ.
In generators of sound in the conventional electronic organs, the combination of oscillators and frequency dividers is used to produce the square waves with a fundamental frequency corresponding a key pressed and square waves with a frequency of an integral multiple of the fundamental frequency. These square waves are combined or synthesized in a desired ratio, and the combined or synthesized output is made to pass through a tone filter so that undesired frequency spectrum may be removed. Moreover, in general, the direct keying system is used for intermittently interrupting the square wave trains with the above harmonic series. However, a large number of filters are required in order to determine a desired ratio in which the harmonic components are combined and to produce various timbres, so that the conventional electronic organs are complex in construction and expensive. In order to overcome this problem, there has been proposed a system in which timbres are combined into groups each consisting of a few or several or tens timbres and these timbre groups are made to pass through low-pass filters. However, this system has a defect that the timbres and volume are considerably different at high and low tones. Furthermore, it is difficult to simplify the construction so that the associated circuits may not be fabricated in the form of LSI.